The present invention relates to a surgical device having a clipping instrument to be inserted through a forceps channel of an endoscope.
Generally, in a clipping instrument for endoscopic surgeries, a clip having a pair of openable/closable arms and a fastening ring loosely fit around proximal portions of the arms is arranged in a distal end portion of a flexible sheath. The clip is configured such that the arms open and close as an operation wire, arranged in parallel with an axial direction of the flexible sheath, is advanced toward the distal end to push the fastening ring and retracted toward a proximal end to pull the fastening ring. The clip can be detached from the operation wire with its arms closed according to the operations to the operation wire. Such a configuration of the clipping instrument is disclosed in Japanese Patent Provisional Publication No. 2006-87537, for example.
When the clip of such conventional clipping instrument disclosed in the aforementioned publication is operated to be clipped onto in vivo tissue to indwell inside a body cavity, the arms are fully opened to their extent to be pressed onto the tissue and closed.
Therefore, the clipping instrument is provided a sleeve having a plurality (for example, three or four) of slits, which are parallel to an axial direction, at the distal end of the flexible sheath so that the fastening ring can resiliently outstretch the sleeve and penetrate therethrough, and the arms can be maintained open.
It is to be noted that after the fastening ring passed through the sleeve, the proximal portion of the clip remains inside the sleeve, and an outline of the remaining proximal portion is generally smaller than an outer diameter of the fastening ring. Therefore, the proximal portion may not be firmly held by the sleeve as the sleeve resiliently deforms, and the arms projecting out of the sleeve may be unstable and undesirably swayed. Thus, the clip may not be accurately handled to be pressed to a targeted portion of the body tissue.